In this paper a design of a voltage controlled amplifier is described together with its practical realization and measured parameters. The amplifier is supposed to be employed in audio signal processing systems, for example volume expanders, etc. The design was created with the aid of several software supports as Maple for mathematical description of the circuit or Multisim for complex analysis of the amplifier's behaviour. The verification of the design was done by practical construction and performance measurements. The discussion on the differences between the simulated and really obtained results is also included in the framework of this paper.